Refresh the page you want to share and now the external user invite is allowed.

Done! Now you are able to share a modern SharePoint Online site with guest users. A better approach I use is to create a group and share with external users, that way security and content are isolated from employee content.

5 thoughts on “SharePoint Online Communication site – How to share with external users”

I’ve found when doing this with a Modern Communications site it prompts you for authentication in the browser when it first loads the site. This is using an Azure B2B guest access that I’ve shared a Modern Communications Site with. Any ideas why?

Hi Paul, are you referring to the SharePoint Online sign in prompt? If you are familiar with the SAML Claims authentication (similar to AD FS), you know about the browser session cookie that stores the users authentication. If you clear your cookies/cache or use another browser or private browsing, this cookie is discarded and the user is prompted again to sign in. To enable SSO to Office 365, there really is no “Never prompt me again” since technically any account can have access to any tenant so an automatic link is not pre-determined by the OS/domain/website.
Let me know if I missed what you are saying and I can help out! Thanks for reading.